Electricity is used for powering a wide variety of devices, across areas such as manufacturing, air conditioning, and information technology (IT), to name a few. Electricity can be delivered as alternating current (AC) or direct current (DC). AC power can be delivered at a variety of voltage levels and phase configurations (e.g. two-phase and three-phase). For large-scale industrial applications, electricity costs can be a considerable portion of the operating budget. Furthermore, in an IT application there can be many devices such as servers, storage devices, routers, and other communications and monitoring equipment placed together in racks. Data centers can house many rows of racks, and thus the power consumption of the data centers can be very high at times. Additionally, the power demand for both industrial applications and data centers can fluctuate based on various business factors such as time of day or season. Thus, managing power becomes an important aspect in many industrial applications, including data center administration. Even further, any energy savings achieved can translate into increased profits for an organization. Additionally, energy savings can provide additional dividends in terms of reduced wear and tear on power sources and reduced cooling costs, adding to an organization's received benefit.
In the case of data centers, also known as “server farms,” there can be hundreds or even thousands of racks. The devices on the racks typically provide functionality including the storage, processing, and retrieval of data. Given the power requirements demanded by the rack-mounted devices, reliable and efficient power delivery is crucial for successful operation of the organizations using the data centers. In some cases, the reliability and availability requirements placed on the devices powering the data center infrastructure must meet or exceed predetermined statutory requirements, as is the case for financial institutions.
No matter the type of institution however, important issues such as availability, reliability, job load, and other organizational requirements of data centers, mean that various infrastructure requirements must be met. For example, the issue of effectively cooling a data center (i.e. the removal of excess heat) is a critical issue which must be addressed to ensure stable and reliable operation of the data center. Each of the many devices in the data center generates substantial amounts of heat, whether the device is a server, a blade, a switch, a backup unit, a communications unit, or another device. The cooling of modern data centers can directly impact the layout and design of the center. Another significant data center design consideration involves providing sufficient power to the data center. Particularly in the case of high-reliability data centers, such as those used for e-commerce, banking, airline reservations, video distribution, and the like, power can be provided by more than one power grid, while for other data centers, power can be provided by a combination of a power grid and locally generated power. Regardless of how the power is delivered to the data center, providing reliable and efficient power to the large number of computers and associated equipment in modern data centers or server farms is an important aspect of successful operation of such facilities.